1. Field of the Invention
This invention relates generally to construction and carpentry equipment and tools, and more particularly to anchoring devices for string/chalk lines and plumb bobs and to protective and safety sheaths for such tools.
2. Related Art
In building construction and carpentry projects, alignment strings and chalk lines are frequently used to confirm or establish straight lines. Such strings (or lines) have one portion that serves to store the unused portion of the string, e.g. a simple ball of string or, as is often the case, a reel of some sort is used to pay-out and pay-in the line. The other “free” end of the line is usually held by an assistant or anchored by a mechanical device. Such mechanical devices typically include a nail, an awl, a stickpin, and so forth. Frequently commercial chalk lines include an L-shaped hook with an eyelet tied to the line's free end. The hook is used to anchor the line over the edge of a work piece. After the chalk line is properly positioned, the line is plucked near its center to cause a chalk mark to be left on the surface of the underlying material.
All of the above mentioned anchoring devices see considerable use at construction job sites. The stickpin is one of the more commonly used string line anchoring devices. These pins are about the size of an adult finger and have the general shape of the body of a dart (without feathers). The forward end of the stickpin, as in a dart, includes a highly sharpened, needle like point. In use, the string is tied around an annular groove in the stickpin, the pin is pressed by hand into the work surface and the line is then looped around the needle portion immediately adjacent to the surface. The other end of the line is then pulled to tighten the string against the stickpin. The needle portion of the stickpin is typically formed from a high strength steel so that it may be pushed by hand, without damaging the point, into a variety of non-metallic materials, such as wood, plywood, sheetrock, etc.
A significant disadvantage of known stickpins is that the length of the needle cannot be adjusted to allow the body of the stickpin to serve as a fixed stop for the insertion of the needle into materials of differing hardness. This capability is desirable so that the pin is not inserted further than is needed to satisfactorily anchor the string. If it is inserted too far it will leave an excessively large hole when it is removed. Also, the risk of breaking the needlepoint is also increased when it is inserted too far. Should the sharpened point be broken, in some cases it may be resharpened, if not, the tool must be discarded.
Plumb bobs are also frequently used by carpenters and other construction industry professionals. As is well known, a plumb bob is used to determine the “plumbness” or verticality of a wall, stud column, etc. It also is used to vertically transfer a point at one elevation to another elevation.
In laying out construction projects, plumb bobs are frequently used in concert with string lines and chalk lines. The availability of a tool that integrates all the features of a string/chalk line stickpin anchoring device and a plumb bob would increase the efficiency of the carpenter and reduce overall expenses to the project. In addition, a tool that would allow replacement of a broken point in the stickpin would further increase the efficiency of the carpenter and decrease his/her equipment costs.
U.S. Pat. No. 5,720,113 teaches an integrated string line anchoring device and plumb bob which is especially designed to accommodate the use of an L-shaped eyelet hook on the end of the string line. This prior tool has a dart-shaped body terminating in a sharpened point to serve as a stickpin anchor. The body has a recess for holding the L-shaped eyelet hook at the end of a string. The tool further incorporates a threaded cap that releasably retains the hook within the recess in the body. This tool is not configured for field replacement of the sharpened point. To serve as a plumb bob, the threaded cap is removed to reveal a groove in the body in which the string is placed to allow the tool to be suspended from it central axis, thus serving as a plumb bob. Alternatively, a slot may be provided in the cap to allow the string to be routed to the central axis suspension point.
There is still a need for a string line tool that may be easily mounted on a string line box and easily handled and used either as a string line anchor or a plumb bob. There is still a need for a string line tool with a durable and reliable spike for insertion into wood and other building materials, wherein the spike is adjustable and/or replaceable. Embodiments of the present invention meet these needs. There is also a need for a sheath for such tools that protects the spike from damage and protects users from the spike, and that keeps the tool in an easily-reachable and convenient location.